CNC Machine Monitoring: What and How?

time clock 10 min read • February 18, 2020 CNC machine OEE

Evocon monitors production on a variety of CNC (computer numerical control) machines from different manufacturers in metal and plastics processing.

Processes:

Lasers, plasma cutters, water jets, CNC lathes, milling and punching machines, and more.

Machine producers:

ESAB, Doosan, Okuma,  Haas, Fermat, Finnpower,  Amada, Bystronic, Feeler etc.

What can you monitor if you have a CNC machine?

In standard production processes, we usually measure single pieces against a set target cycle time. However, in CNC machine monitoring it is often difficult to measure the processing time of single units against targets. This is because of the broad range of custom orders and combinations of part layouts on raw material.

  • Monitoring effective work time (availability)
    Typically, you would measure machine’s operating time, compared to it’s planned production time (planned production time is equal to scheduled work shifts minus planned stops). This approach offers a good insight into the utilisation rate of the equipment and stop reasons, e.g. loading, unloading, transporting material, cleaning, technical stops, breaks, organisational issues.
  • Counting pieces
    Depending on the machine and process, you could count the number of parts produced. In addition to effective work time, this option measures the processing time of a part against a set target time.

As the first step when starting to monitor machines, we recommend monitoring effective work time. The implementation process is quicker and after some experience with the system, you can progress to counting pieces if it creates more value.

How do you monitor a CNC machine with Evocon?

Monitoring CNC machine’s effective work time

To track when the machine is working, you need to connect the system to the machine’s spindle, laser, Andon light or any electrical circuit that has current going through during the processing cycle. Your local maintenance personnel can do this by themselves or with some assistance from Evocon if needed.

Counting pieces produced by a CNC machine

The best way to count produced pieces is to configure the G-code of the machine. G-code can provide signals from the machine about the operational status (working in automatic mode or not working). Sometimes, the code can be modified to send signals to a relay each time the machine finishes a part.

The latest CNC machines have up to 4 relays that you can use as outputs for other devices. The Evocon’s IIoT device can read the signal from the relay and interpret it as a finished product.

Evaluating the performance of a CNC machine

  • When monitoring CNC machine’s effective working time, you can measure only the availability component of the OEE. Evocon’s Shift View would show processing time in green and idle time in red colour.
  • When counting produced pieces, you need to define a target or ideal cycle time for each part in Evocon. The system compares this value to the actual processing time for that part and then calculates and visualises performance (production speed during processing).

Do you need an Evocon’s IIoT device for monitoring CNC machines?

To connect machines using one of the methods described above, you need the Evocon device to collect and send data to a server. However, it is possible to monitor CNC machines without the Evocon device. Some machines can be configured to send HTTPS requests directly to Evocon system.